fumarates and 3-methylglutaconic-acid

Single large-scale mitochondrial DNA deletions disorders are classified into three main phenotypes with frequent clinical overlap: Pearson marrow-pancreas syndrome (PMS), Kearns-Sayre syndrome (KSS) and chronic progressive external ophtalmoplegia (PEO). So far, only few anecdotal studies have reported on the urinary organic acids profile in this disease class. In this single-center retrospective study, we performed quantitative evaluation of urinary organic acids in a series of 15 pediatric patients, 7 with PMS and 8 with KSS. PMS patients showed an organic acids profile almost constantly altered, whereas KSS patients frequently presented with normal profiles. Lactate, 3-hydroxybutyrate, 3-hydroxyisobutyrate, fumarate, pyruvate, 2-hydroxybutyrate, 2-ethyl-3-hydroxypropionate, and 3-methylglutaconate represented the most frequent metabolites observed in PMS urine. We also found novel metabolites, 3-methylglutarate, tiglylglycine and 2-methyl-2,3-dihydroxybutyrate, so far never reported in this disease. Interestingly, patients with a disease onset as PMS evolving overtime into KSS phenotype, presented persistent and more pronounced alterations of organic acid signature than in patients with a pure KSS phenotype. Our study shows that the quantitative analysis of urinary organic acid profile represents a helpful tool for the diagnosis of PMS and for the differential diagnosis with other inherited diseases causing abnormal organic acidurias.

Topics: 3-Hydroxybutyric Acid; Acyl-CoA Dehydrogenase, Long-Chain; Adolescent; Child; Child, Preschool; Congenital Bone Marrow Failure Syndromes; DNA, Mitochondrial; Fumarates; Glutarates; Humans; Hydroxybutyrates; Infant; Kearns-Sayre Syndrome; Lactic Acid; Lipid Metabolism, Inborn Errors; Mitochondrial Diseases; Muscular Diseases; Pyruvic Acid; Retrospective Studies; Valerates

The prevalence of 3-methylglutaconic aciduria was evaluated among children with developmental language disorders. A urine specimen was obtained from 40 children referred for developmental language delay to the Tel-Aviv Child Development Center during 12/96-6/97 and from 50 age-matched controls. Urine organic acids were analysed by gas chromatography-mass spectrometry. Urinary 3-methylglutaconic acid was quantified. A mildly increased excretion of 3-methylglutaconic acid was found in 8 children with developmental language delay. The combined excretion of 3-methylglutaconic and 3-methylglutaric acid was increased in 9 patients. There were no differences in the excretion of other organic acids. The patients with elevated 3-methylglutaconic acid did not differ from the other patients with developmental language disorders in any of the parameters evaluated. Mildly elevated urinary levels of 3-methylglutaconic acid may be a marker of a still undefined metabolic disorder presenting with developmental language delay. A further study in large groups of children with different developmental disorders is mandatory.

Topics: Child; Child, Preschool; Female; Fumarates; Glutarates; Humans; Language Development Disorders; Male; Malonates; Mass Screening; Meglutol

Seven boys with an apparently X-linked syndrome of dilated cardiomyopathy, growth retardation, neutropenia, and persistently elevated urinary levels of 3-methylglutaconate, 3-methylglutarate, and 2-ethylhydracrylate were studied. The natural history of the disorder was characterized by severe or lethal cardiac disease and recurrent infections during infancy and early childhood but relative improvement in later childhood. The initial presentation of the syndrome varied from congenital dilated cardiomyopathy to infantile congestive heart failure to isolated neutropenia without clinical evidence of heart disease. The excretion of 3-methylglutaconate and 3-methylglutarate appeared to be independent of the metabolism of leucine, the presumed precursor of these organic acids in humans. Although the cause of the organic aciduria remains obscure, the constellation of biochemical and clinical abnormalities forms a distinct syndrome that may be a relatively common cause of dilated cardiomyopathy or neutropenia in boys during infancy and childhood.

Topics: Adult; Cardiomyopathy, Dilated; Child; Child, Preschool; Chromatography, High Pressure Liquid; Fumarates; Glutarates; Growth Disorders; Heart Failure; Humans; Male; Meglutol; Muscular Diseases; Neutropenia; Pedigree; Syndrome; X Chromosome